Series 3500 Pilot Operated Relief Valves

Superior Pressure Relief Products

2 Hydroseal Series 3500 Pilot Operated Relief Valve

Hydroseal Series 3500 Pilot Operated Relief ValveThe Hydroseal Series 3500 is a high performance pilot operatedsafety relief valve that is offered in both Modulating and Snapaction. Useful for air, gas, mixed phase and liquid services, thesevalves are designed for reliable operation, long seat life andeasy low cost field service. The Series 3500 product line isoffered in a wide range of orifices, materials, pressures andtemperature ranges.

General Design Features Proven Soft Seat Design:

Hydroseal's unique capturedo-ring design used acrossmany of our other productlines allows many differentElastomers to be offered atthe lowest cost possible. Usingstandard size o-rings also allowsfor easy replacement.

Seat Tightness: The difference in areaof the dome side and the seat side ofthe piston keeps the main valve bubbletight right up to the set pressure. Pilotvalves are an excellent choice forapplications with operating pressuresvery close to set pressure.

Snap Action: The snap action control pilot fully opens themain valve at set pressure achieving full capacity untilthe reseat point is reached and the main valve closes.The snap pilot has an adjustable blowdown and is builtfor minimal maintenance and easy repair. Standard forair and gas only.

Modulating Action: Ideal for applications where a minimalamount of product loss is critical. The modulating controlpilot gradually opens and closes the main valve to relieveonly the excess pressure in a system. It will fully openthe main valve before 10% overpressure is reached.Standard for liquid and optional for air and gas.

Easy Repair: All seals are o-rings that are easily replacedand are offered in a wide array of materials such asFluorocarbon, Nitrile and PTFE. The main valve's boltedconstruction allows for easy disassembly.

Orifice Areas: All orifice sizes meet or exceed competitorsdimensions for easy interchangeable replacement.

API Dimensions: Main valve centerline to face dimensionsmeet API 526.

Accessories Field Test Connection: Allows for in service testing of the

valve by charging the pilot through a test port reducingmaintenance and system down time.

Back-Flow Preventer: Prevents backpressure on themain valve outlet from opening the main valve by allowingthe outlet pressure to charge the dome when the backpressure exceeds the inlet pressure.

Pressure Snubber: Filters out pressure spikes in the inletpressure that can cause the main valve to pop early.

Filter: Recommended for extra dirtyservice that could cause blockages orwear to the control pilot valve.

Lift Lever: Another option for in servicetesting. By lifting a handle, the controlpilot is opened thereby opening themain valve until the handle is released.

Remote Sensing:Allows the set pressuresignal to come from somewhere otherthan the inlet of the main valve. Byleaving the sense line off the pilot valveand plugging the pitot, the end usercan plumb the supply pressure from adifferent location.

Inlet x Orifice

Nozzle Diameter Nozzle AreaLift

Max.Outlet in. cm in.2 cm2 Pressure

D 0.437 1.11 0.150 0.971 x 2 E 0.560 1.42 0.246 1.59

F 0.688 1.75 0.372 2.40 0.350 in.

11/2D 0.437 1.11 0.150 0.97 8.89cm

6170E 0.560 1.42 0.246 1.59

psi(g)x 2F 0.688 1.75 0.372 2.40

425.511/2 G 0.871 2.21 0.596 3.84 0.572 in.

bar(g)x 3 H 1.125 2.86 0.994 6.41 14.53cm

G 0.871 2.21 0.596 3.840.703 in.

2 x 3 H 1.125 2.86 0.994 6.41J 1.382 3.51 1.500 9.68

17.86cm

J 1.382 3.51 1.500 9.681.049 in.

3 x 4 K 1.653 4.20 2.146 13.853705

L 2.063 5.24 3.343 21.5726.64cm

psi(g)L 2.063 5.24 3.343 21.57

255.54 x 6

M 2.314 5.88 4.206 27.14 1.590 in.bar(g)

N 2.537 6.44 5.054 32.61 40.39cmP 3.125 7.94 7.670 49.48

6 x 8Q 4.060 10.31 12.946 83.52 2.484 in. 1480 psi(g)R 4.882 12.40 18.719 120.77 63.09 cm 102.1bar(g)

8 x 10 T 6.257 15.89 30.748 198.383.183 in. 900 psi(g)80.85cm 62.1 bar(g)

Size & Range

3Hydroseal Series 3500 Pilot Operated Relief Valve

Hydroseal Series 3500 Operation, Snap & Modulating Action

Snap Action PilotBelow Set Pressure: The pilot allows the inlet pressure topass through and charge the dome of the main valve keepingthe main valve seat tightly closed.

Above Set Pressure: The pilot upper seat lifts fully ventingthe dome pressure to atmosphere allowing the main valvepiston to rise opening the main valve. Simultaneously, thepilot lower seat closes keeping the inlet pressure from the mainvalve from re-charging the dome. When the inlet pressuredrops to the reseat point, the pilot lower seat opens and thepilot upper seat closes, recharging the dome and closing themain valve.

Modulating Action PilotBelow Set Pressure: The pilot allows the inlet pressure topass through and charge the dome of the main valve keepingthe main valve seat tightly closed.

Above Set Pressure: The modulating pilot allows the domepressure to be vented gradually in proportion with theincrease in inlet pressure. As the inlet pressure increases from100% to 110% of set pressure, the main valve goes fromclosed to full open. As the system pressure drops below theset pressure, the modulating pilot gradually recharges thedome of the main valve in proportion with the drop in systempressure, closing the main valve.

Closed Position

Inlet Pressure Less Than Set Pressure

Dome Pressure EqualTo Inlet Pressure

Main ValvePilot

Dome PressureVenting To ATM

Relieving Position

Inlet Pressure Greater Than Set Pressure

Vent To

ATM

Main ValvePilot

FlowTo

ATM

Modulating Closed Position

Inlet Pressure Less Than Set Pressure

Dome Pressure EqualTo Inlet Pressure

Main Valve

Pilot Vent

Modulating Relieving Position

Inlet Pressure Greater Than Set Pressure

Dome Pressure LessThan Inlet Pressure

Main Valve

FlowTo

ATM

Pilot Vent

4 Hydroseal Series 3500 Pilot Operated Relief Valve

Hydroseal Series 3500, Weights & Dimension Data

Orifice Inlet x Outlet Class Max. SetDimensions (in.) Weight (approx.)

A B C lbs. kg1 x 2 150 x 150 285 4.12 4.50 14.50 24 10.91 x 2 300 x 150 740 4.37 4.50 14.62 26 11.81 x 2 600 x 150 1480 4.37 4.50 14.62 26 11.8

D 1 x 2 900/1500 x 300 3705 4.93 4.75 15.25 32 14.5

API Area .110 in.2 / .71 cm21 x 2 2500 x 300 6170 4.93 4.75 15.25 35 15.9

Actual Area .150 in.2 / .97 cm21 1/2 x 2 150 x 150 285 4.87 4.75 15.00 26 11.81 1/2 x 2 300 x 150 740 4.87 4.75 15.00 30 13.61 1/2 x 2 600 x 150 1480 4.87 4.75 15.00 30 13.61 1/2 x 2 900/1500 x 300 3705 5.87 5.50 16.25 40 18.21 1/2 x 2 2500 x 300 6170 5.87 5.50 16.25 50 22.7

1 x 2 150 x 150 285 4.12 4.50 14.50 24 10.91 x 2 300 x 150 740 4.37 4.50 14.62 26 11.81 x 2 600 x 150 1480 4.37 4.50 14.62 26 11.8

E 1 x 2 900/1500 x 300 3705 4.93 4.75 15.25 32 14.5

API Area .196 in.2 / 1.27 cm21 x 2 2500 x 300 6170 4.93 4.75 15.25 35 15.9

Actual Area .249 in.2 / 1.59 cm21 1/2 x 2 150 x 150 285 4.87 4.75 15.00 26 11.81 1/2 x 2 300 x 150 740 4.87 4.75 15.00 30 13.61 1/2 x 2 600 x 150 1480 4.87 4.75 15.00 30 13.61 1/2 x 2 900/1500 x 300 3705 5.87 5.50 16.25 40 18.21 1/2 x 2 2500 x 300 6170 5.87 5.50 16.25 50 22.7

1 x 2 150 x 150 285 4.12 4.50 14.50 24 10.91 x 2 300 x 150 740 4.37 4.50 14.62 26 11.81 x 2 600 x 150 1480 4.37 4.50 14.62 26 11.8

F 1 x 2 900/1500 x 300 3705 4.93 4.75 15.25 32 14.5

API Area .370 in.2 / 1.98 cm21 x 2 2500 x 300 6170 4.93 4.75 15.25 35 15.9

Actual Area .372 in.2 / 2.40 cm21 1/2 x 2 150 x 150 285 4.87 4.75 15.00 26 11.81 1/2 x 2 300 x 150 740 4.87 4.75 15.00 30 13.61 1/2 x 2 600 x 150 1480 4.87 4.75 15.00 30 13.61 1/2 x 2 900/1500 x 300 3705 5.87 5.50 16.25 40 18.21 1/2 x 2 2500 x 300 6170 5.87 5.50 16.25 50 22.71 1/2 x 3 150 x 150 285 5.12 4.87 16.12 58 26.41 1/2 x 3 300 x 150 740 5.12 4.87 16.12 61 27.71 1/2 x 3 600 x 150 1480 5.12 4.87 16.12 61 27.7

G 11/2 x 3 900/1500 x 300 3705 6.37 6.75 18.62 95 43.2

API Area .503 in.2 / 3.25 cm21 1/2 x 3 2500 x 300 6170 6.37 6.75 18.62 104 47.3

Actual Area .596 in.2 / 3.84 cm22 x 3 150 x 150 285 5.37 4.87 16.87 59 26.82 x 3 300 x 150 740 5.37 4.87 16.87 62 28.22 x 3 600 x 150 1480 5.37 4.87 16.87 62 28.22 x 3 900/1500 x 300 3705 6.56 6.75 18.87 103 46.82 x 3 2500 x 300 6170 7.00 6.75 19.25 115 52.3

1 1/2 x 3 150 x 150 285 5.12 4.87 16.12 58 26.41 1/2 x 3 300 x 150 740 5.12 4.87 16.12 61 27.71 1/2 x 3 600 x 150 1480 5.12 4.87 16.12 61 27.7

H 11/2 x 3 900/1500 x 300 3705 6.37 6.75 18.62 95 43.2

API Area .785 in.2 / 5.06 cm21 1/2 x 3 2500 x 300 6170 6.37 6.75 18.62 104 47.3

Actual Area .994 in.2 / 6.41 cm22 x 3 150 x 150 285 5.37 4.87 16.87 59 26.82 x 3 300 x 150 740 5.37 4.87 16.87 62 28.22 x 3 600 x 150 1480 5.37 4.87 16.87 62 28.22 x 3 900/1500 x 300 3705 6.56 6.75 18.87 103 46.82 x 3 2500 x 300 6170 7.00 6.75 19.25 115 52.3

5Hydroseal Series 3500 Pilot Operated Relief Valve

Hydroseal Series 3500, Weights & Dimension Data

Orifice Inlet x Outlet Class Max. SetDimensions (in.) Weight (approx.)

A B C lbs. kg2 x 3 150 x 150 285 5.37 4.87 16.87 59 26.82 x 3 300 x 150 740 5.37 4.87 16.87 62 28.22 x 3 600 x 150 1480 5.37 4.87 16.87 62 28.2

J 2 x 3 900/1500 x 300 3705 6.56 6.75 18.87 103 46.8

API Area 1.287 in.2 / 8.30 cm22 x 3 2500 x 300 6170 7.00 6.75 19.25 115 52.3

Actual Area 1.500 in.2 / 9.68 cm23 x 4 150 x 150 285 6.12 6.37 18.12 100 45.53 x 4 300 x 150 740 6.12 6.37 18.12 106 48.23 x 4 600 x 150 1480 6.37 6.37 18.12 106 48.23 x 4 900 x 300 2220 7.50 7.12 20.00 141 64.13 x 4 1500 x 300 3705 7.50 7.12 20.00 153 69.53 x 4 150 x 150 285 6.12 6.37 18.12 100 45.5

K 3 x 4 300 x 150 740 6.12 6.37 18.12 106 48.2API Area 1.838 in.2 / 11.86 cm2 3 x 4 600 x 150 1480 6.37 6.37 18.12 106 48.2

Actual Area 2.146 in.2 / 13.85 cm2 3 x 4 900 x 300 2220 7.50 7.12 20.00 141 64.13 x 4 1500 x 300 3705 7.50 7.12 20.00 153 69.53 x 4 150 x 150 285 6.12 6.37 18.12 100 45.53 x 4 300 x 150 740 6.12 6.37 18.12 106 48.23 x 4 600 x 150 1480 6.37 6.37 18.12 106 48.2

L 3 x 4 900 x 300 2220 7.50 7.12 20.00 141 64.1

API Area 2.853 in.2 / 18.41 cm23 x 4 1500 x 300 3705 7.50 7.12 20.00 153 69.5

Actual Area 3.343 in.2 / 21.57 cm24 x 6 150 x 150 285 7.75 8.25 21.37 184 83.64 x 6 300 x 150 740 7.75 8.25 21.37 192 87.34 x 6 600 x 150 1480 7.75 8.25 21.37 202 91.84 x 6 900 x 300 2220 9.81 9.18 24.00 285 129.54 x 6 1500 x 300 3705 9.81 9.18 24.00 300 136.44 x 6 150 x 150 285 7.75 8.25 21.37 184 83.6

M 4 x 6 300 x 150 740 7.75 8.25 21.37 192 87.3API Area 3.600 in.2 / 23.23 cm2 4 x 6 600 x 150 1480 7.75 8.25 21.37 202 91.8

Actual Area 4.206 in.2 / 27.41 cm2 4 x 6 900 x 300 2220 9.81 9.18 24.00 285 129.54 x 6 1500 x 300 3705 9.81 9.18 24.00 300 136.44 x 6 150 x 150 285 7.75 8.25 21.37 184 83.6

N 4 x 6 300 x 150 740 7.75 8.25 21.37 192 87.3API Area 4.340 in.2 / 28.00 cm2 4 x 6 600 x 150 1480 7.75 8.25 21.37 202 91.8

Actual Area 5.054 in.2 / 32.61cm2 4 x 6 900 x 300 2220 9.81 9.18 24.00 285 129.54 x 6 1500 x 300 3705 9.81 9.18 24.00 300 136.44 x 6 150 x 150 285 7.75 8.25 21.37 184 83.6

P 4 x 6 300 x 150 740 7.75 8.25 21.37 192 87.3API Area 6.380 in.2 / 41.16 cm2 4 x 6 600 x 150 1480 7.75 8.25 21.37 202 91.8

Actual Area 7.670 in.2 / 49.48 cm2 4 x 6 600 x 300 1480 9.81 9.18 24.00 276 125.54 x 6 900 x 300 2220 9.81 9.18 24.00 285 129.54 x 6 1500 x 300 3705 9.81 9.18 24.00 300 136.36

Q 6 x 8 150 x 150 285 9.43 9.50 25.62 352 160.0API Area 11.050 in.2 / 71.29 cm2 6 x 8 300 x 150 740 9.43 9.50 25.62 369 167.7

Actual Area 12.946 in.2 / 83.52 cm2 6 x 8 600 x 150 1480 9.68 9.50 25.87 394 179.1

R 6 x 8 150 x 150 285 9.43 9.50 25.62 352 160.0API Area 16.000 in.2 / 103.23 cm2 6 x 8 300 x 150 740 9.43 9.50 25.62 369 167.7

Actual Area 18.719 in.2 / 120.77cm2 6 x 8 600 x 150 1480 9.68 9.50 25.87 394 179.1

T 8 x 10 150 x 150 285 10.87 11.00 27.37 511 232.3API Area 26.000 in.2 / 167.74 cm2 8 x 10 300 x 150 740 10.87 11.00 27.37 534 242.7

Actual Area 30.748 in.2 / 198.38cm2 8 x 10 600 x 150 900 11.68 11.00 28.12 575 261.4

6 Hydroseal Series 3500 Pilot Operated Relief Valve

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Hydroseal Series 3500, Parts List & Materials

Index Description Material1 Cap 316SS2 Adjusting Screw 316SS3 Pilot Bonnet 316SS4 Top Adaptor 316SS5 Spring 316SS *6 Body 316SS7 Large Clamp Ring 316SS8 Upper Diaphragm Viton

9 Input Module Body 316SS10 Stop Pin 316SS11 Input Spindle 316SS12 Lower Diaphragm Viton

13 Small Clamp Ring 316SS14 Ball Holder 316SS15 Ball 316SS16 Control Module Body 316SS17 Control Spindle 316SS

18 Control SpringInconel

X75019 Spring Nut 316SS

*Inconel X750 spring used for material codes 2 &4.

Parts List & MaterialsModulating Action Pilot

Index Description Material1 Cap 316SS2 Adjusting Screw 316SS3 Pilot Bonnet 316SS4 Top Adaptor 316SS5 Spring 316SS*6 Lower Spring Plate 316SS7 Disc 316SS8 Pilot Disc Guide 316SS9 Pilot Body 316SS10 Pilot Seat Cap 316SS11 Pilot Nozzle 316SS

12 Pilot Nozzle SealGasket

Material

13 Blowdown Seat 316SS14 Blowdown Shuttle 316SS

15 Blowdown 316SSAdjustment Housing

16 Blowdown 316SSAdjustment Nut

*Inconel X750 spring used for material codes 2 &4.

Parts List & MaterialsSnap Action Pilot

Index DescriptionMaterial

0 2 3 41 Tube SS SS SS SS2 Tube Fitting Straight CS CS SS SS3 Tube Fitting 90 CS CS SS SS4 Bracket CS CS SS SS5 Bonnet SA36 SA36 316SS 316SS6 Return Spring 316SS X750 316SS X7507 Guide 17-4 PH 17-4 PH 316SS 316SS8 Piston 316SS 316SS 316SS 316SS9 Body WCB WCB CF8M CF8M10 O-Ring Retainer 316SS 316SS 316SS 316SS11 Nozzle 316SS 316SS 316SS 316SS12 Pitot 316SS 316SS 316SS 316SS

Parts List & Materials, Series 3500 Relief Valve

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7Hydroseal Series 3500 Pilot Operated Relief Valve

Hydroseal Series 3500, Parts Number Codes & Engineering Data

35 X X X X X X X X X / XX

S Snap (Air/Gas Only)C NeopreneE EPDM

1 1"A 1.5"

D D E EF FG G

2 2"3 3"

A 150 x 150B 300 x 150

1 RF x RF

0 CS Std.2 CS NACE

B Backflow Preventer

Consult Factory for Spring Chart.

*Multiple options can be selected.

Seat M

aterial

Type

Inlet Siz

e

Orifice

Outlet S

ize

Flange C

lass

Facing

Materia

l

Options

*

Spring R

ange

4 4"6 6"

H HJ JK KL L

M MN NP P

Q QR RT T

4 4"6 6"

C 600 x 150D 900 x 300

E 1500 x 300F 2500 x 300

T TeflonV Viton

3 SS Std.4 SS NACE

F FilterL Lift Lever

2 2"3 3"

8 8"

8 8"10 10"

3 RTJ x RTJ

S SnubberU Unloader

M Modulating (Air/Gas & Liquid)K KalrezN Nitrile

2 RTJ x RF

Sizing Equations

W= CK d AP1

Air/Gas

Liquid

Where

US Units

MTZ

Q= 38K d K v A P1- Pd

G

C= 520 2

kk+1k -1

k+1

P1=1.1 Pset +14.7 Over 30 psi OrP1= Pset +17.7 Under 30 psi

Air/Gas

LiquidP1- Pd

GK d K v A 11.78

MTZ

W=13160 CKd AP1

Q=

C= 520 2

kk+1k -1

k+1

Where

SI Units

P1=1.1 Pset +101.3 Over 207 kPa OrP1= Pset +122 Under 207 kPa

TemperatureSeat Material

Nitrile EPDM Viton Neoprene Kalrez Teflon

Lower F -65 -70 -15 -45 30 -300Upper F 225 300 400 300 550 400

Temperature Limits

W = Capacity in lbm/hrPset= Set Pressure in psigPd = Discharge PressureA = Orifice AreaKd = .878 for Air/GasKd = .784 for LiquidKv = Viscosity Correction

FactorQ = Capacity in GPMZ = Compressibility FactorT = Temperature in Rk = Ratio of Specific HeatsM = Molecular WeightG = Specific Gravity

W = Capacity in kg/hrPset= Set Pressure in kPagPd = Discharge PressureA = Orifice AreaKd = .878 for Air/GasKd = .784 for LiquidKv = Viscosity Correction

FactorQ = Capacity in liter/minZ = Compressibility FactorT = Temperature in Kk = Ratio of Specific HeatsM = Molecular WeightG = Specific Gravity

Worldwide Sales Offices

Hydroseal, a leading brand of KF Industries, reaches into every corner of the globe serving the oil & gas and industrial marketplace.

Supplying an extensive range of product offerings

through a worldwide network of manufacturer representatives and distributors,

Hydroseal is the right choice for all your pressure relief needs.

World Headquarters

Hydroseal

1500 S.E. 89th Street

Oklahoma City, OK 73149 USA

Phone: (405) 631-1533

Fax: (405) 631-5034

E-mail: sales@circorenergy.com

www.circorenergy.com

Local Representative

www.circorenergy.comHydro-Pilot3500-June-09-HP 2009 CIRCOR Energy Products, Inc. Hydroseal is a KF Industries Brand Litho USA Hydroseal reserves the right to change designs, materials orspecifications without notice or without obligation to furnish or install such changes on products previously or subsequently sold. Inconel is a registered trademark of Special MetalsCorporation, USA. Teflon is a registered trademark of DuPont. Viton is a registered trademark of DuPont Dow Elastomers.

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accredited by U.K., Dutchand German qualifying

authorities.